Matrix mode provides the user with an easy option of dealing with all the conversation windows. It gathers them all together in a single box so you don’t have to fill your desktop with all of them. I would say Wonderful!!
Check out the screen shot below and I guess that'll summarize what I meant by the Matrix mode.
To activate Matrix Mode, start a few IM conversations and then be sure to condense them into one window as tabs. You can do that by dragging the bottom tab of one window into another, or hitting Ctrl + , (ctrl plus comma) on your keyboard. Once your conversations are in a tabbed window, hit Ctrl + Alt + Shift + b to enter Matrix Mode(Any more key combinations would have resulted in me taking my family member's help). Simply press Pressing Ctrl + Alt + Shift + b.
Hope you found this feature interesting as ever!! But sadly it works only on Windows Vista for now.